well during a full tank fill up of 87 octane i dump a bottle of STP fuel cleaner in there every 4 months or so. im just asking does these cleaners actually work and help clean your fuel line, start up, etc etc...

and would other products be better then STP? more bang for the buck kinda deal, or do these fuel cleaners actually work at all?

They work, yes, but it's not a question of functionality, more of necessity.

Gasoline is a pretty strong solvent, and will break down most contaminants on its own, and if you use quality fuel it should have detergents in it already. I use it regularly when running E85 (E is a terrible solvent), but otherwise it's only an as perceivably necessary deal on pump gas.

I like the redline cleaner, though I can never find it local, only the diesel version, so I always buy it online. I have used it in various cars that i've tracked MPG in have had a 1-4 mpg increase on each one. Good stuff.

From the parts store I was at, everyone swore by Seafoam. Even the other employees. Some liked Lucas also because it supposedly has lubricant for the valves. Usually you don't need it, though. If you want a good clean, take it to redline a few times to get the carbon buildup out a bit. Idling, low RPMs and using too high octane fuel tends to build up carbon. This is one reason why it is better to not idle your car to warm it up in winter, that and it wears faster when cold. Drive it, keeping it low on the RPMs to gently warm it up quickly, less wear in the long run. Works better on auto trans since the fluid goes through the radiator usually and warms up quicker altogether when driven.

On synthetic oil vs dino oil, they are mixable. Synthetic is typically better in every situation. Some people complain about oil leaks, but what happens is, the synthetic usually cleans a little better than dino oil, cleans crud out of seals, basically reveals leaks that were already there but plugged up with crud.

This is one reason why it is better to not idle your car to warm it up in winter, that and it wears faster when cold. Drive it, keeping it low on the RPMs to gently warm it up quickly, less wear in the long run. Works better on auto trans since the fluid goes through the radiator usually and warms up quicker altogether when driven.

wait i dont have to let the car warm in the winter? even if i drive standard. i thought that was always a good thing to let the car warm up a bit.

Using fuel cleaners are absolutely unnecessary (like Spaz has mentioned), unless you run with fuel of really bad quality. Their claims are more of a gimmick than an actual performance enhancement. Just make sure you buy from a reputable gas station (regardless of octane level).

If you really want to clean your fuel system, the proper way to do it is to take it apart and clean it piece by piece or area by area.

In situations where you let your car sit for a long while (months or years) without running the engine, moisture may accumulate in your fuel tank. Use a water removing product before your next fill up to avoid engine problems, when you plan to use the car again.